Question

Phosphorus pentachloride dissociates as follows, in a closed reaction vessel,
$PC{l}_5\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of $PC{l}_5$ is x, the atrial pressure of $PC{l}_3$ will be:

• A. $\left(\frac{2x}{1-x}\right)P$
• B. $\left(\frac{x}{x-1}\right)P$
• C. $\left(\frac{x}{1-x}\right)P$
• D. $\left(\frac{x}{x+1}\right)P$

Answer 1

The correct option is D $\left(\frac{x}{x+1}\right)P$

Let us consider the problem:-

$\underset{1-x}{PC{l}_5}\rightleftharpoons \underset{x}{PC{l}_3}\left(g\right)+\underset{x}{C{l}_2}\left(g\right)$

There fore,

$PC{l}_3=\left(\frac{x}{1+x}\right)\times P$